


Discovery

by moriturus



Category: Frozen (Disney Movies)
Genre: Alternate Universe - Star Trek Fusion, F/F, Incest, Sibling Incest, Star Trek References
Language: English
Status: Completed
Published: 2020-11-21
Updated: 2020-11-21
Packaged: 2021-03-10 08:13:48
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,105
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27650059
Author URL: https://archiveofourown.org/users/moriturus/pseuds/moriturus
Summary: Captain Elsa Nilsen is on a mission to discover what happened to the mycelial network. Her new science officer, Anna Larsen, is eager to help.
Relationships: Anna/Elsa (Disney)
Comments: 5
Kudos: 30





	Discovery

_Warnings: Incest._

# Discovery

_“Captain’s log, stardate 1341.3. We’ve entered orbit around Arktis, a planet in the Carraya system, in search of more of these elusive spores that permit hyperspace travel anywhere in the galaxy. After the disappearance of the USS Discovery, Starfleet has made it a top priority to find whatever these spores are and bring them back for further investigation, with every available ship and crew mustered to duty.”_

Captain Elsa Nilsen closed her log entry and stared at the black glass of her desk, as the stars streaked by out the circular window. These old NX class starships were almost 100 years old, but still serviceable for basic scientific and exploratory missions. Her ship, the _USS Victoria_ , had clearly seen better days. Outfitted with new sensors and a skeleton crew, they were chasing down a lead in the Carraya system. She sighed, mildly irritated that a captain with her stellar record was recalled from extended shore leave and sent out chasing mushrooms across the galaxy.

The ship intercom panel sounded. “Captain Nilsen to the bridge.” Elsa rubbed her face with her hands and pressed the door button from the captain’s ready room onto the cramped bridge. She surveyed her tiny impromptu crew as they eagerly peered at the viewscreen. A green and blue world danced across the screen, cerulean clouds spinning like the inside of a cotton candy machine.

“Lieutenant…” Elsa looked at the new red-headed science officer they’d brought aboard at Starbase 234, drawing a blank on her name. She was usually so good at remembering names, doubly so when they were paired with such a pretty face. “I apologize, Lieutenant?”

“Me? Me Lieutenant?”

Elsa nodded and gestured impatiently.

“Oh! Um, hi. Sorry, Captain. I’m Lieutenant Anna Larsen, science officer. Can I just say what an honor it is to serve with you, Captain?” The new science officer somehow managed to look both flustered and chipper at the same time.

Elsa pushed down a familiar twinge in her gut at the lieutenant’s effortless appeal. She’d been deployed for nearly a decade now in one posting or another, never enough time to settle down and find any kind of companionship. A sense of isolation and loneliness had grown within her the last few years, but her duties made it impossible to satisfy any of them. “Yes, thank you, Lieutenant. Ahem. Please report on what it is we’re looking at?” she prompted, corralling her wandering thoughts.

Anna looked into her viewer, calibrating it. “I’m… not really sure, Captain. These readings don’t make a ton of sense.”

“How so, Lieutenant?” Elsa moved to sit down in her captain’s chair in the center of the bridge.

“According to these readings, the world below should be a frozen hellscape. It’s far enough away from this system’s star that it should be an ice giant…”

“But?”

Anna squinted into her display. “But it’s showing as… habitable. Class L, believe it or not.” She scratched her head absentmindedly. “That shouldn’t be possible this far away from the star. I mean, it’s not possible. Every science textbook since the 20th century would say this far out, it should be a big popsicle. Well, actually, there are some physic-”

“Lieutenant!” Elsa snapped. “Please focus. You said the world is habitable. Any signs of spores or other mycelial life forms?”

“Yes, Captain. The atmosphere itself is clear, but there appear to be spores all over the surface of the planet.”

 _Maybe this isn’t a wild goose chase after all,_ she thought to herself, frustration abating. “Can you get a reading of what the spores are?”

Anna shook her head, red ponytail bouncing from shoulder to shoulder. “No ma’am. We’re too far away to get an accurate reading of what kind of spores these are.”

Elsa stared at the blue planet slowly spinning. “Very well. Lieutenant Larsen, prepare your equipment for an away mission.” Elsa gestured towards Lieutenant Gale, her Benzite security officer. “Gale, grab a couple of your security folks and head for the transporter room. We’re going down there. Ensign Westergaard?”

The young, red-headed ensign at the helm who had been ogling Anna since she came aboard quickly snapped to attention. “Yes, Captain?”

“Maintain our present position. And this time, please try not to crash the ship into anything.” Elsa smiled and turned to the comm panel on her chair as the young ensign blushed and stared intently as his console. “Kristoff? Report to the bridge; we’re heading down to the planet’s surface and need someone senior on the bridge.”

* * *

Five columns of sparkling light appeared on the surface of the planet, a cloud of light blue dust dancing in the wind around them as the away team materialized on the surface. Elsa and Gale surveyed the landscape as Anna scanned the dust, and Gale’s two Benzite security officers ensured the area was safe.

“Captain, my instruments show that the air is breathable.” She removed her mask and was greeted by a cool, musty breeze. The landscape was a pale blue and mostly barren; rocks littered the ground, but the world showed no other significant signs of life. Anna buzzed with excitement; this was her first planetary scientific expedition since her promotion to Lieutenant, and Captain Nilsen had a reputation as one of the service’s more distinguished captains in exploration and discovery.

“Well, Lieutenant? Are these the spores Starfleet has us chasing the galaxy to find?” Elsa asked, removing her mask and allowing her hair to flow in the dusty winds. She took a slow breath at first, then relaxed after feeling no obvious harm. The rest of the landing party did the same. She watched the new lieutenant go through the motions of scanning the spores. Elsa’s eyes wandered over Anna’s form, tracing her curves even in the EVA suits they were wearing. Her mouth ran dry as Anna bent over to obtain a soil sample.

Gale coughed once, then more loudly. Her Benzite breathing apparatus, usually blowing a cold wind of chlorine gas, sputtered in the alien atmosphere. Elsa turned to look at the Benzite, who had turned a distinctly ill-looking shade of blue. “Gale? Are you all right?”

Gale coughed again. “For- forgive me, Captain. I believe I am experiencing an allergic reaction to the dust in the wind. I am finding it difficult to breathe; they are somehow interfering with our air systems.” She turned and saw her companions were equally affected by the dust; one was bent over at the waist trying to catch his breath, the greenish-blue wisps of chlorine gas dissipating faster than he could breathe them in.

“Let’s get you out of here, Gale.” She flipped open her communicator. “Nilsen to _Victoria_ , beam up the security team straight to Sickbay and have Gerda check them out thoroughly.”

The soft whine of transporter beams pulled Gale and her Benzite security officers back to the ship. Elsa let go a breath of relief; Gale was one of her oldest friends. She respected her and cared for her deeply; she was years her senior and wise beyond that, always offering sound, calm, logical advice to her when she needed it most.

Right now, she needed it. Ever since the new lieutenant had come aboard, Elsa had felt some kind of pull towards her, but on this alien world, the gentle tug had practically become a tractor beam. The air was cold, almost frosty, but she felt as though she were on fire.

She turned her attention back to her science officer, who was also looking unusually flushed. Sweat was beading on Anna’s brow.

“Any progress, Lieutenant?”

Anna turned to look at the senior officer. A million thoughts and words raced through her mind as she breathed heavily, her pupils fully dilated. “Please, it’s Anna,” she said with a smile.

“I’m sorry?”

“Please, Captain… Elsa, call me Anna. Lieutenant is such a mouthful, and I’d rather we be friends,” she smiled more broadly and took a step forward into Elsa’s personal space, her cheeks blushing.

“That’s… Lieutenant, the spores. Please.”

Anna looked down briefly at her tricorder. “They’re having some kind of psychological effect on us, but nothing like what happened to Commander Gale. It’s something… more… pleasant.” Anna stepped forward again.

Elsa coughed and stepped back, raising her hands. “Lieutenant! A-Anna… this is conduct unbecoming an officer… of Starfleet… your eyes… so beautiful…” she murmured. Elsa blinked, fighting a maelstrom of emotions inside of her. What was happening to her? She felt like a starship caught in the gravity well of a black hole. All her normal defenses, all her standard precautions against showing her emotions crumbled faster than a Betazoid in a room of drunks.

Anna removed her EVA suit’s gloves and brought her hand to the soft skin of Elsa’s cheek. “You’re beautiful…ler, Elsa… your skin feels so cool and soft. I… I’ve been watching you since I came aboard, and I knew I had to touch you.”

Elsa removed her gloves as well, cupping Anna’s chin. She almost felt like a passenger in her own body as she closed the distance between them. _“Some kind of psychological effect” was an understatement, to say the least._ Elsa stared hungrily at Anna’s lips, and before she knew it, she was pressing her own lips to Anna’s.

Anna inhaled sharply and wrapped her arms around Elsa’s torso, kissing Elsa back as eagerly as she was being kissed. Desire flared in her; had the EVA suits not been so well-secured, she would have already been out of hers. As Elsa plastered kisses on the side of Anna’s neck, she whispered into the captain’s ear. “I- I want you, Elsa. I want you so badly. I feel like I’ve been waiting my whole life for a woman like you.”

Elsa murmured as she trailed kisses down Anna’s neck. “So have I. I’ve never done anything like this before, but I want you. I need you, Anna. I want to discover every inch of your body and feel every emotion in your heart.”

She withdrew from the embrace and stared hungrily at her science officer. “Did you collect enough samples?”

Anna nodded, running the tip of her tongue over her lips to enjoy the aftertaste of Elsa’s lips. “Let’s… let’s take these back to… ummm, to the ship so that we can get out of these suits and learn more about each other. Wait, no, I mean, so we can learn more about these spores.“

Elsa grinned lasciviously and flipped open her communicator. “Nilsen to _Victoria_. Two to beam directly to… Deck E Science Lab 4. Enact biohazard containment protocol theta upon our arrival.” She winked at Anna. “No one will disturb us until we clear the protocol.”

The gentle whine of the transporter beam took the two from the planet’s surface to the ship.

* * *

Elsa wove her hair back into a French braid as she put her uniform back on, smoothing the creases out of it after she’d unceremoniously flung it to the floor of the lab earlier. Anna did much the same, tying her red hair back into pigtails and wiping her body clean with a damp lab towel. She let her eyes wander over her captain’s body, basking in the afterglow of what she’d shared with her.

“That was…”

“It was, yes.” Elsa smiled, blushing. “I trust, Lieutenant, that we can be discreet about this part of our mission?”

Anna smiled and nodded vigorously. “As long as this part of our mission isn’t over, Captain. I’d like to keep exploring… you.”

Elsa’s cheeks reddened further as she cleared her throat. “Let’s… table that for another time. We should probably head to Sickbay to get checked out.”

“After you, Captain,” Anna grinned, gesturing to the door.

“Computer, disengage theta protocol and reactivate all systems,” the Captain commanded. “We should probably head for Sickbay to, um, confirm everything’s all right.”

Anna nodded and followed the senior officer as she contemplated what had just happened. She’d been attracted to the captain ever since coming aboard, that much was true. Elsa was just so inspiring, so confident. But she’d never even contemplated making such strong advances, much less outright fucking someone in such a short time. Was it the planet? The spores they’d brought back?

Elsa’s mind was just as confused and buzzing as Anna’s. What she’d done - what she’d allowed to happen - could potentially be a court-martial offense, fraternizing with a junior officer directly under her command. Regardless of who initiated it, she would easily be found guilty if the matter ever became public. Shame and passion warred inside her heart and stomach as she suppressed any outward signs of her inner turmoil.

Dr. Gerda Jorgensen greeted the two officers as they entered the Victoria’s tiny medical center. Gale and the Benzite security guards slept soundly in three of the bays. “Ah, Captain, Lieutenant, excellent. I trust everything went smoothly?”

Elsa coughed. “Yes, Doctor. We were able to secure some samples…” Elsa turned to Anna, who eagerly waited to share the results.

“The spores aren’t an exact match for the mycelium Starfleet is looking for. Nonetheless, we were able to obtain detailed scans and bring some samples back. They appear to be harmful to Benzites, it looks like?” Anna gestured towards the sleeping security contingent.

Gerda ran a tricorder over both women as she spoke. “They’ll be fine. It appears that the spores somehow absorbed the chlorine gas as it came out of their breathing apparatus. Did you notice any effects on yourselves?”

Both officers blushed, and Anna stifled a yelp into her fist.

“No, Doctor, nothing significant. Are we all right?” asked Elsa nervously.

“I am detecting elevated levels of both cortisol and oxytocin in you both, but nothing that requires treatment. Let me just run a scan to ensure there are no mutagenic properties…” Gerda stopped suddenly, then pushed a few buttons on the scanner. “Captain… may I have a word with you privately?”

“Of course. I’ll be back momentarily, Lieutenant,” she said too briskly, following the doctor into her office.

* * *

Once the chief medical officer’s door had closed, Gerda spoke as she walked past Elsa. “Captain, how well do you know Lieutenant Larsen?”

Elsa shook her head, willing herself not to blush, not to think about how well she knew every curve of Anna’s body. “The Lieutenant came aboard a few days ago at Starbase 24. I’ve never met her before.” Dread suddenly filled Elsa’s stomach as she started to pace in the tiny office. “Is she all right? Is something wrong with her?”

Gerda patted Elsa on the shoulder before taking a seat behind her desk. “No, both you and the Lieutenant are in fine health. Your trip to the planet doesn’t appear to have caused you any illness. However, I found something when I did the mutagenic scan.”

Elsa’s anxieties did not ease. Mutagenic scans looked for deformations and mutations in DNA, signs of genetic damage done by outside influences. “Is the Lieutenant carrying some form of genetic disease?”

“No. Captain… do you have any siblings?”

“No, none. My parents vanished when I was very young, and I spent thirteen years in orphanages and foster care until the Academy. I’ve no records of any living relatives, not for lack of trying on my part,” she grumbled.

Gerda slid the medical tricorder across the desk wordlessly, knowing Elsa’s scientific background could easily make sense of the DNA scans.

“… impossible…” Elsa collapsed into the chair across from the doctor, stunned. “She… Doctor, how is it possible that Lieutenant Larsen… is my sister?”

“I’m afraid we’ll need to ask the Lieutenant that. Are you all right, Captain? I imagine this is a bit of a shock, but you appear to be mortified. I would have thought you’d been more excited to learn you had a sister, given how you’ve said you missed such interactions growing up.” Gerda reached across the desk to retrieve her tricorder.

“I… I’m just a little… shocked. That’s all, Doctor. Just… shocked.” Elsa stood up, willing her trembling hands under control. Chaos swirled in her mind. Not only did she behave inappropriately towards a junior officer under her command, somehow that junior officer was also her blood relations. Conduct unbecoming an officer didn’t even begin to describe incest. She felt almost as though she’d fallen into some nightmarish alternate reality. “Let’s have the Lieutenant join us.”

* * *

“Lieutenant Larsen, would you please sit down?” asked Gerda, gesturing to the seat next to Elsa in the cramped office.

“Is… am I dying? Oh gods, are the spores going to eat me alive? I knew I shouldn’t have taken my helmet off so quickly! What if they’re secretly the eggs of a face-hugging alien that-”

“Lieutenant!” Elsa interrupted, pinching the bridge of her nose. “The doctor assures me you are the picture of perfect health.”

Gerda smiled. “Yes. Now, before we continue, Lieutenant, would you indulge me in a line of inquiry about your family history?”

Anna shrugged. “Sure, it’s not all that exciting. I grew up way far out in the Antos sector. I’m an orphan; I was raised by a family of scientists on Antos IV. That’s how I got my interests in scientific exploration.”

“Do you remember your parents at all?” asked Elsa softly.

“Vaguely. I know their names, Iduna and Agnar-” Anna looked quizzically at Elsa’s sudden gasp. “But I don’t really remember them all that well. I don’t even know exactly how old I am; my birthdate and age were given to me by my adoptive family. I wish I did know more.”

“This may come as a shock to you, Lieutenant, but you and the Captain… well, there’s no easy way to say this. You are genetically related to the Captain.”

“Related?” Anna yelled. “Related how?” she asked, staring at Elsa.

“We… we are sisters. Long-lost sisters.” Elsa covered her face in shame.

“Oh my gods, that’s amazing!” Anna cheered. She leaped out of her chair and awkwardly embraced Elsa. “I’ve always dreamed of having a sister! I spent years just wandering the halls of my foster-” Anna stopped suddenly as the implications of what she’d done with Elsa hit her.

“Lieutenant? Are you alright? You look quite pale all of a sudden,” remarked Gerda.

“I- um- she- sister- yeah! Yeah, I’m fine. Just fine, absolutely fine, nothing to worry about or think about or wonder if you… yeah. I’m good,” Anna stuttered nervously, grinning wildly to hide her embarrassment.

“I think the Lieutenant and I will take some time to digest this… information, Doctor. Thank you for your assistance,” Elsa said wanly, leaving the medical office with Anna in tow.

* * *

“So… sisters,” Anna started, once the door to Elsa’s ready room closed and locked.

Elsa sighed and leaned against the desk, sitting on the edge. “We are. That said, I would have thought there would have been more of an age difference than there is; you’re barely 3 years younger than me.”

Anna sat down next to her. “That’s what happens when you grow up near a large temporal vortex. It would have been 13 years out here since our parents disappeared for you, but on Antos IV, it was close to double that.”

“So… we’re blood relatives. Siblings. Sisters.” Elsa looked down at her hands, nervously. “That’s quite a discovery.” She turned her gaze back to Anna, her emotions at war. Lust. Disgust at herself. Want. And a desperate need to earn Anna’s love, to fill the empty void in her heart from years of wandering the galaxy alone.

“I have another discovery for you, sis.”

Elsa winced silently.

“Too soon?”

A nod.

“All right, well, while you and Dr. Jorgensen were talking, I finished my analysis of the spores. Want to guess what effect they have on humans?” Anna said, just slightly smirking.

Elsa let out a long breath. “Let me guess, they have aphrodisiac and adaptogenic properties?”

Anna shook her head, smiling more broadly. “Close, but no. They function more like a truth serum - lowering inhibitions and enhancing truth-telling. Which means…”

Elsa stared into Anna’s eyes, holding her gaze level. “We both wanted… that.”

“We did. And I still do, you know.”

“How could you, knowing that we’re sisters?”

Anna turned to face Elsa, putting an arm around her shoulders. “Are we? We grew up decades apart in totally separate parts of the quadrant. We didn’t know each other until a few days ago. And while there might be some genetic sexual attraction, I am totally okay with it because as familiar as you are, you’re also still a total stranger to me.”

Elsa failed to suppress a smirk of her own. “Not a total stranger, mind you. We have, umm…”

“Fucked. You can say it, Elsa. We fucked, it was wonderful, and I can’t wait to do it again if you’ll have me.” Both women’s cheeks blushed furiously as they subconsciously moved closer to each other. “That said, there’s still so much more to discover, to explore.”

Elsa raised a hand to her sister’s cheek. “And I’d love to explore it with you.” She touched her lips to Anna’s and hugged her tightly.

* * *

_“Captain’s log, stardate 1357.7. While we had no success finding spores for accessing the mycelial network, we did find some spores that seem to enhance truth-telling. Starfleet’s Section 31 has asked us to bring back as many samples as possible for study and replication, and have put in a commendation for the crew, especially for my new-ish lieutenant… and sister. We now head for the Unroth system to continue our search.”_

Elsa tapped the console to end her log entry and looked at the small framed photo on her desk of her parents. Anna had found a copy in her belongings and had it replicated for her, which was a sweet gesture, even though Elsa barely remembered them.

As she contemplated the strange twist of fate that had brought her a long-lost sister, the door chimed. “Come!” she said briskly.

“Usually that happens after I’m in the room,” Anna said with a mischievous grin. She walked around Elsa’s desk and kissed her, then sat on Elsa’s lap. “So… any word?” she asked, tracing Elsa’s jawline playfully.

Elsa coughed. “No, not yet, though we should be hearing from the Judge Advocate General’s office shortly.” She glanced to ensure the ready room door was locked, then pulled Anna down for a kiss of her own. Just as she started weaving her fingers through Anna’s hair, her console sounded.

“Incoming transmission from Starbase 157,” the computer said mirthlessly.

Anna quickly jumped off Elsa’s lap and straightened her uniform, suppressing a wry smile as Elsa tugged on her uniform jacket, smoothing it out. “Accept and display.”

“Captain Nilsen.” A dour Vulcan appeared onscreen. “This is Rear Admiral Kai of the Judge Advocate General Corps.”

Elsa unconsciously sat up straighter. “Yes, Admiral?”

The Vulcan held up a PADD just offscreen. “To your inquiry about your new crew member, Lieutenant Larsen of Antos IV, Starfleet Command judges that given the circumstances, and knowing you were not raised together, that she may continue to serve under your command. Starfleet Regulation 1138 Gamma does not apply to you or Lieutenant Larsen on a familial basis, and has been noted in both your service records.”

Elsa let go of the breath she was holding. “Thank you, Admiral. I will note that in the ship’s log as well.”

The Vulcan nodded once wordlessly and summarily ended the transmission. Anna squealed with delight, hugging Elsa awkwardly. “Elsa! I’m so excited! I get to stay aboard the _Victoria_!”

Elsa smiled. “You do, yes. But,” she straightened again, “I will remind you that we must continue to be discreet. Regulation 1138 also encompasses romantic relationships, and I don’t want either of us to get into trouble, okay?”

Anna nodded. “Speaking of romantic relationships…”

Elsa smirked as she stood up, making her way to the door. “I’m off duty at 1800 hours, Lieutenant. My quarters.” She turned to Anna with her hand on the locking mechanism. “Don’t be late… or clothed.”

* * *

## Author’s Notes

This fic was part of the August 2020 Elsanna Shenanigans contest. The theme Discovery inspired it, and what the Federation might have been trying to do to fix/restore the spore drive concept.

* * *

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